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A high-performance liquid chromatography analysis of plasma artemisinin using a glassy carbon electrode for reductive electrochemical detection

Chan KL, Yuen KH, Jinadasa S, Peh KK, Toh WT

Planta Med, 1997 Feb;63(1):66-9.
PMID: 9063097

A high-performance liquid chromatography assay equipped with a glassy carbon electrode for electrochemical detection (HPLC-ECD) was developed at reductive mode for the analysis of artemisinin, the antimalarial drug from Artemisia annua (Asteraceae) in human plasma. This method was selective, sensitive, and produced satisfactory recovery, precision, and accuracy. Analysis of plasma samples from 8 male volunteers given 10 mg kg-1 of artemisinin orally as an aqueous suspension showed a mean peak plasma concentration (Cmax) of 580.89 ng ml-1 +/- 88.64 SD at 2.5 h +/- 0.5 SD after dosing, and the mean area under the plasma concentration-time curve (AUC0-infinity) was 2227.57 ng h ml-1 +/- 677.22 SD. In addition, the elimination rate constant (Ke), elimination half-life (t1/2), and apparent volume of distribution (Vd) were calculated to be 0.2971 h-1 +/- 0.0644 SD, 2.42 h +/- 0.46 SD, and 16.26 l kg-1 +/- 3.44 SD, respectively.

Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
Liquid Chromatographic Analysis of α-Dicarbonyls Using Girard-T Reagent Derivatives

Lawrence GD, Rahmat R, Makahleh A, Saad B

J Chromatogr Sci, 2017 Nov 01;55(10):1043-1050.
PMID: 28977384 DOI: 10.1093/chromsci/bmx073

The measurement of α-dicarbonyls and other degradation products of sugars has become important in view of their toxicity. Although there are several methods used for their analysis, most require long reaction times to form UV absorbing or fluorescent derivatives and the nonpolar nature of commonly used derivatives necessitates relatively high concentrations of organic solvents for elution in reverse phase liquid chromatography. The present method describes the use of Girard-T reagent in a simple, one step derivatization of α-dicarbonyls and conjugated aldehydes and analysis using ion-pair reverse phase liquid chromatography. The limit of detection was in the range of 0.06-0.09 μM (4-12 ng/mL) for glyoxal, methylglyoxal, 3-deoxyglucosone and 5-hydroxymethylfurfural with good linear response and reproducibility using UV detection. The hydrazone derivatives were stable for several days in solution. The method was used to study degradation of several sugars and quantification of the target α-dicarbonyls and 5-hydroxymethylfurfural in several soft drinks.

Matched MeSH terms: Chromatography, Liquid/methods*
Discovery of Antimalarial Drugs from Streptomycetes Metabolites Using a Metabolomic Approach

Ahmad SJ, Abdul Rahim MBH, Baharum SN, Baba MS, Zin NM

J Trop Med, 2017;2017:2189814.
PMID: 29123551 DOI: 10.1155/2017/2189814

Natural products continue to play an important role as a source of biologically active substances for the development of new drug. Streptomyces, Gram-positive bacteria which are widely distributed in nature, are one of the most popular sources of natural antibiotics. Recently, by using a bioassay-guided fractionation, an antimalarial compound, Gancidin-W, has been discovered from these bacteria. However, this classical method in identifying potentially novel bioactive compounds from the natural products requires considerable effort and is a time-consuming process. Metabolomics is an emerging "omics" technology in systems biology study which integrated in process of discovering drug from natural products. Metabolomics approach in finding novel therapeutics agent for malaria offers dereplication step in screening phase to shorten the process. The highly sensitive instruments, such as Liquid Chromatography-Mass Spectrophotometry (LC-MS), Gas Chromatography-Mass Spectrophotometry (GC-MS), and Nuclear Magnetic Resonance ((1)H-NMR) spectroscopy, provide a wide range of information in the identification of potentially bioactive compounds. The current paper reviews concepts of metabolomics and its application in drug discovery of malaria treatment as well as assessing the antimalarial activity from natural products. Metabolomics approach in malaria drug discovery is still new and needs to be initiated, especially for drug research in Malaysia.

Matched MeSH terms: Chromatography, Liquid; Gas Chromatography-Mass Spectrometry
Cyclodextrin based polymer sorbents for micro-solid phase extraction followed by liquid chromatography tandem mass spectrometry in determination of endogenous steroids

Manaf NA, Saad B, Mohamed MH, Wilson LD, Latiff AA

J Chromatogr A, 2018 Mar 30;1543:23-33.
PMID: 29478831 DOI: 10.1016/j.chroma.2018.02.032

Sorbents were prepared by cross-linking β-cyclodextrin (β-CD) using two different types of cross-linker units at variable reactant mole ratios. The resulting polymers containing β-CD were evaluated as sorbents in micro-solid phase extraction (μ-SPE) format for the extraction of the endogenous steroids testosterone (T), epitestosterone (E), androsterone (A), etiocholanolone (Etio), 5α-androstane-3α,17β-diol (5αAdiol) and 5β-androstane-3α,17β-diol (5βAdiol). The best sorbent (C1; cyclodextrin polymer) showed superior extraction characteristics compared with commercial sorbents (C18 and Bond Elut Plexa). Parameters influencing the extraction efficiency of the C1 sorbent such as extraction and desorption times, desorption solvent and volume of sample were investigated. The extracts were separated using a Hypersil Gold column (50 × 2.1 mm, 1.9 μm) under gradient elution coupled to a LC-MS/MS. The compounds were successfully separated within 8 min. The method offers good repeatability (RSD  0.995) were within the range of 1-200 ng mL-1 for T and E, 250-4000 ng mL-1 for A and Etio and 25-500 ng mL-1 for 5αAdiol and 5βAdiol, respectively. The method was applied for the determination of steroid profile of urine from volunteers.

Matched MeSH terms: Chromatography, Liquid*
Estimation of uncertainty from method validation data: Application to a reverse-phase high-performance liquid chromatography method for the determination of amino acids in gelatin using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent

Azilawati MI, Dzulkifly MH, Jamilah B, Shuhaimi M, Amin I

J Pharm Biomed Anal, 2016 Sep 10;129:389-397.
PMID: 27454091 DOI: 10.1016/j.jpba.2016.07.012

A detailed procedure for estimating uncertainty according to the Laboratory of Government Chemists/Valid Analytical Measurement (LGC/VAM) protocol for determination of 18 amino acids in gelatin is proposed. The expanded uncertainty was estimated using mainly the method validation data (precision and trueness). Other sources of uncertainties were contributed by components in standard preparation measurements. The method scope covered a single matrix (gelatin) under a wide range of analyte concentrations. The uncertainty of method precision, μ(P) was 0.0237-0.1128pmolμl(-1) in which hydroxyproline and histidine represented the lowest and highest values of uncertainties, respectively. Proline and phenylalanine represented the lowest and highest uncertainties value for method recovery, μ(R) that was estimated within 0.0064-0.0995pmolμl(-1). The uncertainties from other sources, μ(Std) were 0.0325, 0.0428 and 0.0413pmolμl(-1) that were contributed by hydroxyproline, other amino acids and cystine, respectively. Hydroxyproline and phenylalanine represented the lowest and highest values of expanded uncertainty, U(y) that were determined at 0.0949 and 0.2473pmolμl(-1), respectively. The data were accurately defined and fulfill the technical requirements of ISO 17025:2005.

Matched MeSH terms: Chromatography, Reverse-Phase/methods
Simultaneous determination of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 in human serum by ultra performance liquid chromatography: An economical and validated method with bovine serum albumin

Chin SF, Osman J, Jamal R

Clin Chim Acta, 2018 Oct;485:60-66.
PMID: 29935177 DOI: 10.1016/j.cca.2018.06.024

A simple and economical method has been developed for simultaneous determination of human serum 25-hydroxyvitamin D2 (25OHD2) and 25-hydroxyvitamin D3 (25OHD3) using Ultra Performance Liquid Chromatography (UPLC). Non-human matrix of 4% BSA was used to construct the calibration curve and in quality control samples' preparation to avoid interference of the endogenous 25-hydroxyvitamin D (25OHD) present in the human serum. 25OHD2, 25OHD3 and dodecanophenone (internal standard, IS) were separated on a CORTECS solid-core particle column and monitored by photodiode array detector at wavelength of 265 nm within five min run time. The relationship between 25OHD concentration and peak area ratio (25OHD:IS) was linear over the range of 12.5 - 200 nM with mean correlation coefficients (r2) >0.998. The limit of detection (LOD) for 25OHD2 and 25OHD3 was 3.00 nM and 3.79 nM, while the lower limit of quantification (LLOQ) was 9.11 nM and 11.48 nM, respectively. High repeatability was obtained for both isomers with intra-day CV% <5.6% and <5.3% for inter-day assay. This method was further tested with a commercial lyophilized serum control with an accuracy of 92.87-108.31% and applied on 214 human serum samples. In summary, this validated method with BSA can be reliably applied for routine quantification of 25OHD in adults.

Matched MeSH terms: Chromatography, High Pressure Liquid/economics
Fulltext MECP2 mutations in Malaysian Rett syndrome patients

Fong CB, Thong MK, Sam CK, Mohamed Noor MN, Ariffin R

Singapore Med J, 2009 May;50(5):529-33.
PMID: 19495527

Rett syndrome (RS) is a severe neurodevelopmental disorder characterised by normal neurological development followed by progressive developmental regression. The X-linked dominant inheritance of RS has been mapped to the gene that encodes the methyl-CpG-binding protein-2 (MECP2) at Xq28. In the present study, denaturing high-performance liquid chromatography (DHPLC) was used to detect mutations in the MECP2 gene in 20 Malaysian RS patients.

Matched MeSH terms: Chromatography, High Pressure Liquid/methods
Production of gasoline range hydrocarbons from catalytic cracking of linoleic acid over various acidic zeolite catalysts

Gurdeep Singh HK, Yusup S, Quitain AT, Kida T, Sasaki M, Cheah KW, et al.

Environ Sci Pollut Res Int, 2019 Nov;26(33):34039-34046.
PMID: 30232774 DOI: 10.1007/s11356-018-3223-4

Employment of edible oils as alternative green fuel for vehicles had raised debates on the sustainability of food supply especially in the third-world countries. The non-edible oil obtained from the abundantly available rubber seeds could mitigate this issue and at the same time reduce the environmental impact. Therefore, this paper investigates the catalytic cracking reaction of a model compound named linoleic acid that is enormously present in the rubber seed oil. Batch-scale experiments were conducted using 8.8 mL Inconel batch reactor having a cyclic horizontal swing span of 2 cm with a frequency of 60 cycles per minute at 450 °C under atmospheric condition for 90 min. The performance of HZSM-5, HBeta, HFerrierite, HMordenite and HY catalysts was tested for their efficiency in favouring gasoline range hydrocarbons. The compounds present in the organic liquid product were then analysed using GC-MS and classified based on PIONA which stands for paraffin, isoparaffin, olefin, naphthenes and aromatics respectively. The results obtained show that HZSM-5 catalyst favoured gasoline range hydrocarbons that were rich in aromatics compounds and promoted the production of desired isoparaffin. It also gave a higher cracking activity; however, large gaseous as by-products were produced at the same time.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods
Fulltext Assessing product adulteration of Eurycoma longifolia (Tongkat Ali) herbal medicinal product using DNA barcoding and HPLC analysis

Abubakar BM, Salleh FM, Shamsir Omar MS, Wagiran A

Pharm Biol, 2018 Dec;56(1):368-377.
PMID: 30058427 DOI: 10.1080/13880209.2018.1479869

CONTEXT: Eurycoma longifolia Jack (Simaroubaceae) commonly known as Tongkat Ali is one of the most important plants in Malaysia. The plant extracts (particularly roots) are widely used for the treatment of cough and fever besides having antimalarial, antidiabetic, anticancer and aphrodisiac activities.
OBJECTIVES: This study assesses the extent of adulteration of E. longifolia herbal medicinal products (HMPs) using DNA barcoding validated by HPLC analysis.
MATERIALS AND METHODS: Chloroplastic rbcL and nuclear ITS2 barcode regions were used in the present study. The sequences generated from E. longifolia HMPs were compared to sequences in the GenBank using MEGABLAST to verify their taxonomic identity. These results were verified by neighbor-joining tree analysis in which branches of unknown specimen are compared to the reference sequences established from this study and other retrieved from the GenBank. The HMPs were also analysed using HPLC analysis for the presence of eurycomanone bioactive marker.
RESULTS: Identification using DNA barcoding revealed that 37% of the tested HMPs were authentic while 27% were adulterated with the ITS2 barcode region proven to be the ideal marker. The validation of the authenticity using HPLC analysis showed a situation in which a species which was identified as authentic was found not to contain the expected chemical compound.
DISCUSSION AND CONCLUSIONS: DNA barcoding should be used as the first screening step for testing of HMPs raw materials. However, integration of DNA barcoding with HPLC analysis will help to provide detailed knowledge about the safety and efficacy of the HMPs.

Matched MeSH terms: Chromatography, High Pressure Liquid/methods
A highly selective two-way purification method using liquid chromatography for isolating αS2-casein from goat milk of five different breeds

Mohsin AZ, Sukor R, Selamat J, Meor Hussin AS, Ismail IH, Jambari NN, et al.

J Chromatogr B Analyt Technol Biomed Life Sci, 2020 Dec 01;1160:122380.
PMID: 32971369 DOI: 10.1016/j.jchromb.2020.122380

The main challenges in the purification of αS2-casein are due to the low quantity in milk and high homology with other casein subunits, i.e., αS1-casein, β-casein, and κ-casein. To overcome these challenges, the aim of this study was to develop a two-step purification to isolate native αS2-casein in goat milk from five different breeds; British Alpine, Jamnapari, Saanen, Shami, and Toggenburg. The first step of the purification was executed by anion-exchange chromatography under optimal elution conditions followed by size exclusion chromatography. Tryptic peptides from in-gel digestion of purified αS2-casein were sequenced and analyzed by LC-ESI-MS/MS. From 1.05 g of whole casein, the highest yield of αS2-casein (6.7 mg/mL) was obtained from Jamnapari and the lowest yield (2.2 mg/mL) was from Saanen. A single band of pure αS2-casein was observed on SDS-PAGE for all breeds. The αS2-casein showed coverage percentage of amino acid sequence from 76.68 to 92.83%. The two-step purification process developed herein was successfully applied for isolating native αS2-casein from goat milk with high purity, which will allow for future in vitro studies to be conducted on this protein.

Matched MeSH terms: Chromatography, Liquid/methods*
LC-MS/MS quantitation of antimalarial drug piperaquine and metabolites in human plasma

Aziz MY, Hoffmann KJ, Ashton M

J Chromatogr B Analyt Technol Biomed Life Sci, 2017 Sep 15;1063:253-258.
PMID: 28863865 DOI: 10.1016/j.jchromb.2017.06.035

PURPOSE: This study aimed to develop a sensitive, quantitative assay for the antimalarial piperaquine (PQ) and its metabolites M1 and M2 in human plasma.
RESULTS: Analytes were gradiently separated on a C18 column and detected with a Sciex API 4000 MS/MS with an ESI source operated in the positive ion mode with deuterated PQ as internal standard. The response was linear in the range 3.9-2508nM with a runtime of 7.0min per sample. The method was applied to clinical samples from healthy volunteers.
CONCLUSION: This LC-MS/MS method for the simultaneous quantitation of PQ and two of its metabolites in plasma may prove helpful for assessment of metabolite safety issues in vivo.

Matched MeSH terms: Chromatography, Liquid/methods*
HPLC-MS/MS method for bioavailability study of bruceines D & E in rat plasma

Man F, Choo CY

J Chromatogr B Analyt Technol Biomed Life Sci, 2017 Sep 15;1063:183-188.
PMID: 28869873 DOI: 10.1016/j.jchromb.2017.08.037

Bruceines D and E are quassinoids from seeds of Brucea javanica (L.) Merr. exhibiting hypoglycemia effect. The crude drug is used as a traditional medicine by diabetes patients. The aim of this study is to understand the bioavailability and pharmacokinetics of both the bruceines D & E. A rapid and sensitive HPLC-MS/MS method was developed and validated for the quantification of both quassinoids, bruceines D & E in rat plasma. Both the bruceines D & E were separated with the Zorbax SBC-18 column with gradient elution and mobile phase system of acetonitrile and deionized water with 0.1% formic acid at a flow rate of 0.5mL/min. Analytes were detected in multiple reaction monitoring (MRM) mode with electrospray positive ionization. The quassinoids, namely bruceines D & E were detected with transitions of m/z 411.2→393.2 and m/z 395.2→377.2, respectively. Another quassinoid, eurycomanone was used as the internal standard with transition of m/z 409.2→391.2. The method was validated and conformed to the regulatory requirements. The validated method was applied to pharmacokinetic and bioavailability studies in rats. The pharmacokinetic study indicated both bruceine D and E were rapidly absorbed into the circulation system and reached its peak concentration at 0.54±0.34h and 0.66±0.30h, respectively. Bruceine E was eliminated slower than Bruceine D with t1/2 value almost increased two-fold compared to Bruceine D. In conclusion, a rapid, selective and sensitive HPLC-MS/MS method was developed for the simultaneous determination of both the bruceines D and E in rat plasma. Both bruceines D and E displayed poor oral bioavailability.

Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
Analysis of lignans from Phyllanthus niruri L. in plasma using a simple HPLC method with fluorescence detection and its application in a pharmacokinetic study

Murugaiyah V, Chan KL

J Chromatogr B Analyt Technol Biomed Life Sci, 2007 Jun 1;852(1-2):138-44.
PMID: 17261384

A simple analytical method using HPLC with fluorescence detection was developed for the simultaneous determination of four lignans, phyllanthin (1), hypophyllanthin (2), phyltetralin (3) and niranthin (4) from Phyllanthus niruri L. in plasma. The method recorded limits of detection for 1, 2, 3 and 4 as 1.22, 6.02, 0.61 and 1.22 ng/ml, respectively, at a signal-to-noise ratio of 5:1 whereas their limits of quantification were 4.88, 24.41, 4.88 and 9.76 ng/ml, respectively, at a signal-to-noise ratio of 12:1. These values were comparable to those of other sensitive methods such as gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography-MS (HPLC-MS) and HPLC-electrochemical detection (HPLC-ECD) for the analysis of plasma lignans. A further advantage over known methods was its simple protocol for sample preparation. The within-day and between-day accuracies for the analysis of the four lignans were between 87.69 and 110.07% with precision values below 10.51%. Their mean recoveries from extraction were between 91.39 and 114.67%. The method was successfully applied in the pharmacokinetic study of lignans in rats. Following intravenous administration, the lignans were eliminated slowly from the body with a mean clearance of 0.04, 0.01, 0.03 and 0.02 l/kg h and a mean half-life of 3.56, 3.87, 3.35 and 4.40 h for 1, 2, 3 and 4, respectively. Their peak plasma concentration upon oral administration was 0.18, 0.56, 0.12 and 0.62 microg/ml, respectively, after 1h. However, their absorption was incomplete with a calculated absolute oral bioavailability of 0.62, 1.52, 4.01 and 2.66% for 1, 2, 3 and 4, respectively.

Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
Simple, rapid and sensitive assay method for simultaneous quantification of urinary nicotine and cotinine using gas chromatography-mass spectrometry

Man CN, Gam LH, Ismail S, Lajis R, Awang R

J Chromatogr B Analyt Technol Biomed Life Sci, 2006 Dec 5;844(2):322-7.
PMID: 16908224

Nicotine is a major addictive compound in cigarette. Its smoke is rapidly and extensively metabolized to several metabolites in human. Cotinine as a major metabolite of nicotine is commonly used as a biomarker to determine active and passive smokers. Cotinine has a longer half-life ( approximately 20 h) compared to nicotine ( approximately 2h). A simple, sensitive, rapid and high throughput GC-MS method was developed for simultaneous quantification of urinary nicotine and cotinine in passive and active smokers. In the sample preparation method, the analytes and internal standard were first basified and followed by liquid-liquid extraction. Upon completion, anhydrous sodium sulphate was added to the solvent mixture to trap moistures. The clear extract obtained was directly injected into GC-MS, operating under selective ion monitoring (SIM) mode. Calibration curves in the range of 0.5-5000 ng/mL of the analytes in urine matrix were established with linear correlation coefficients (r(2)) greater than 0.997. The limit of detection for both nicotine and cotinine were 0.20 ng/mL. The mean recoveries for nicotine and cotinine were 93.0 and 100.4%, respectively. The within- and between-assay accuracies were between 2.1 and 7.9% for nicotine and between 0.7 and 11.1% for cotinine. Within- and between-assay precisions of 3.3-9.5% for nicotine and 3.4-9.8% for cotinine were also achieved. The method can be used in routine assessment and monitoring of active smoking and exposure to environmental tobacco smoke. The applicability of the assay was demonstrated in a small-scale comparison study between smokers and non-smokers.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*
Liquid chromatographic method for the determination of plasma itraconazole and its hydroxy metabolite in pharmacokinetic/bioavailability studies

Wong JW, Nisar UR, Yuen KH

J Chromatogr B Analyt Technol Biomed Life Sci, 2003 Dec 25;798(2):355-60.
PMID: 14643517

A sensitive and selective high-performance liquid chromatographic method was developed for the determination of itraconazole and its active metabolite, hydroxyitraconazole, in human plasma. Prior to analysis, both compounds together with the internal standard were extracted from alkalinized plasma samples using a 3:2 (v/v) mixture of 2,2,4-trimethylpentane and dichloromethane. The mobile phase comprised 0.02 M potassium dihydrogen phosphate-acetonitrile (1:1, v/v) adjusted to pH 3.0. Analysis was run at flow-rate of 0.9 ml/min with excitation and emission wavelengths set at 260 and 365 nm, respectively. Itraconazole was found to adsorb on glass or plastic tubes, but could be circumvented by prior treating the tubes using 10% dichlorodimethylsilane in toluene. Moreover, rinsing the injector port with acetonitrile helped to overcome any carry-over effect. This problem was not encountered with hydroxyitraconazole. The method was sensitive with limit of quantification of 3 ng/ml for itraconazole and 6 ng/ml for hydroxyitraconazole. The calibration curve was linear over a concentration range of 2.8-720 ng/ml for itraconazole and 5.6-720 ng/ml for the hydroxy metabolite. Mean recovery value of the extraction procedure for both compounds was about 85%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 15%. Hence, the method is suitable for use in pharmacokinetic and bioavailability studies of itraconazole.

Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
Purification of bacteriophage M13 by anion exchange chromatography

Monjezi R, Tey BT, Sieo CC, Tan WS

J Chromatogr B Analyt Technol Biomed Life Sci, 2010 Jul 1;878(21):1855-9.
PMID: 20538529 DOI: 10.1016/j.jchromb.2010.05.028

M13 is a non-lytic filamentous bacteriophage (phage). It has been used widely in phage display technology for displaying foreign peptides, and also for studying macromolecule structures and interactions. Traditionally, this phage has been purified by cesium chloride (CsCl) density gradient ultracentrifugation which is highly laborious and time consuming. In the present study, a simple, rapid and efficient method for the purification of M13 based on anion exchange chromatography was established. A pre-packed SepFast Super Q column connected to a fast protein liquid chromatography (FPLC) system was employed to capture released phages in clarified Escherichia coli fermented broth. An average yield of 74% was obtained from a packed bed mode elution using citrate buffer (pH 4), containing 1.5 M NaCl at 1 ml/min flow rate. The purification process was shortened substantially to less than 2 h from 18 h in the conventional ultracentrifugation method. SDS-PAGE revealed that the purity of particles was comparable to that of CsCl gradient density ultracentrifugation method. Plaque forming assay showed that the purified phages were still infectious.

Matched MeSH terms: Chromatography, Ion Exchange/methods*
Determination of hair nicotine by gas chromatography-mass spectrometry

Man CN, Ismail S, Harn GL, Lajis R, Awang R

J Chromatogr B Analyt Technol Biomed Life Sci, 2009 Jan 15;877(3):339-42.
PMID: 19109080 DOI: 10.1016/j.jchromb.2008.12.014

Hair nicotine is a known biomarker for monitoring long-term environmental tobacco smoke (ETS) exposure and smoking status. In general, hair nicotine assay involves alkaline digestion, extraction and instrumental analysis. The gas chromatography-mass spectrometry (GC-MS) assay currently developed has shown to be of high throughput with average approximately 100 hair samples being extracted and analyzed per day. This was achieved through simplified extraction procedure and shortened GC analysis time. The extraction was improved by using small volume (0.4 mL) of organic solvent that does not require further evaporation and salting steps prior to GC-MS analysis. Furthermore, the amount of hair utilized in the extraction was very little (5 mg) while the sensitivity and selectivity of the assay is equal, if not better than other established methods. The linearity of the assay (r(2)>0.995), limit of quantitation (0.04 ng/mg hair), within- and between-assays accuracies and precisions (<11.4%) and mean recovery (92.6%) were within the acceptable range.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry*
Hollow fiber liquid-phase microextraction combined with high performance liquid chromatography for the determination of trace mitiglinide in biological fluids

Hadi H, Makahleh A, Saad B

J Chromatogr B Analyt Technol Biomed Life Sci, 2012 May 1;895-896:131-6.
PMID: 22503735 DOI: 10.1016/j.jchromb.2012.03.031

A hollow fiber liquid phase microextraction (HF-LPME) in conjunction with reversed phase HPLC-UV method was developed for the extraction and determination of trace amounts of the antidiabetic drug, mitiglinide (MIT) in biological fluids. The drug was extracted from 10 mL aqueous sample (donor phase (DP)) into an organic phase impregnated in the pores of hollow fiber, followed by the back extraction into a second aqueous solution (acceptor phase (AP)) located in the lumen of the hollow fiber. Parameters influencing the extraction efficiency including the kind of organic solvent, composition of DP and AP, extraction time, stirring rate and salt addition were investigated and optimized. Under the optimized extraction conditions, high enrichment factors (210-fold), good linearity (5-1000 ng mL(-1)) and detection limit lower than 1.38 ng mL(-1) were achieved. Recoveries of spiked samples were in the range (88.3-96.3%) and (92.0-99.3%) for urine and plasma samples, respectively. The percent relative standard deviation (n=9) for the extraction and determination of three concentration levels (100, 400 and 800 ng mL(-1)) of MIT were less than 10.6% and 13.6% for urine and plasma samples, respectively. The developed method is simple, sensitive and has been successfully applied to the analysis of MIT in biological fluids.

Matched MeSH terms: Chromatography, High Pressure Liquid/methods*
Chiral liquid chromatography-mass spectrometry (LC-MS/MS) method development for the detection of salbutamol in urine samples

Chan SH, Lee W, Asmawi MZ, Tan SC

J Chromatogr B Analyt Technol Biomed Life Sci, 2016 Jul 01;1025:83-91.
PMID: 27232053 DOI: 10.1016/j.jchromb.2016.05.015

A sequential solid-phase extraction (SPE) method was developed and validated using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the detection and quantification of salbutamol enantiomers in porcine urine. Porcine urine samples were hydrolysed with β-glucuronidase/arylsulfatase from Helix pomatia and then subjected to a double solid-phase extraction (SPE) first using the Abs-Elut Nexus SPE and then followed by the Bond Elut Phenylboronic Acid (PBA) SPE. The salbutamol enantiomers were separated using the Astec CHIROBIOTIC™ T HPLC column (3.0mm×100mm; 5μm) maintained at 15°C with a 15min isocratic run at a flow rate of 0.4mL/min. The mobile phase constituted of 5mM ammonium formate in methanol. Salbutamol and salbutamol-tert-butyl-d9 (internal standard, IS) was monitored and quantified with the multiple reaction monitoring (MRM) mode. The method showed good linearity for the range of 0.1-10ng/mL with limit of quantification at 0.3ng/mL. Analysis of the QC samples showed intra- and inter-assay precisions to be less than 5.04%, and recovery ranging from 83.82 to 102.33%.

Matched MeSH terms: Chromatography, Liquid/methods*
Method development and validation of a high-performance liquid chromatographic method for tramadol in human plasma using liquid-liquid extraction

Gan SH, Ismail R, Wan Adnan WA, Wan Z

J Chromatogr B Analyt Technol Biomed Life Sci, 2002 May 25;772(1):123-9.
PMID: 12016023

An HPLC system using a simple liquid-liquid extraction and HPLC with UV detection has been validated to determine tramadol concentration in human plasma. The method developed was selective and linear for concentrations ranging from 10 to 2000 ng/ml with average recovery of 98.63%. The limit of quantitation (LOQ) was 10 ng/ml and the percentage recovery of the internal standard phenacetin was 76.51%. The intra-day accuracy ranged from 87.55 to 105.99% and the inter-day accuracy, 93.44 to 98.43% for tramadol. Good precision (5.32 and 6.67% for intra- and inter-day, respectively) was obtained at LOQ. The method has been applied to determine tramadol concentrations in human plasma samples for a pharmacokinetic study.

Matched MeSH terms: Chromatography, High Pressure Liquid/methods*

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